Soil-shedding article of footwear, and method of using the same

ABSTRACT

Disclosed herein are articles of footwear, and methods of manufacturing articles of footwear, having an open-cell foam present on at least a portion of the outsole. The open-cell foam is effective in reducing soil accumulation on the outsole when the footwear is worn on unpaved surfaces.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit under 35 USC § 119(e) of U.S.provisional patent application No. 62/042,744 filed Aug. 27, 2014, andU.S. provisional patent application No. 62/042,719 filed Aug. 27, 2014,the disclosures of which are incorporated herein by reference to theextent that they do not conflict with the present disclosure.

FIELD

This application generally relates to articles of footwear, and morespecifically to articles of footwear and components thereof, includingoutsoles, that may be used in conditions conducive to the accumulationof soil on the outsoles.

BACKGROUND

Articles of footwear of various types are frequently used for a varietyof activities including outdoor activities, military use, andcompetitive sports. The outsoles of these types of footwear often aredesigned to provide traction on soft and slippery surfaces, such asunpaved surfaces including grass and dirt. For example, exaggeratedtread patterns, lugs, or cleats (both integral and removable), andrubber formulations which provide improved traction under wetconditions, have been used to improve the level of traction provided bythe outsoles. While these conventional means generally help givefootwear improved traction, the outsoles often accumulate soil (e.g.,inorganic materials such as mud, dirt, sand and gravel, organic materialsuch as grass, turf, and other vegetation, and combinations of inorganicand organic materials) when the footwear is used on unpaved surfaces. Insome instances, the soil can accumulate in the tread pattern (when atread pattern is present), around and between lugs (when lugs arepresent), or on shafts of the cleats, in the spaces surrounding thecleats, and in the interstitial regions between the cleats (when cleatsare present). The accumulations of soil can weigh down the footwear andinterfere with the traction between the outsole and the ground.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the disclosure, reference should bemade to the following detailed description and accompanying drawingswherein:

FIG. 1 is a bottom isometric view of an article of footwear in an aspectof the present disclosure having an outsole including a material (e.g.,a film) in accordance with the present disclosure;

FIG. 2 is a bottom view of the outsole of the article of footwear shownin FIG. 1, where an upper of the footwear is omitted;

FIG. 3 is a lateral side view of the outsole shown in FIG. 2;

FIG. 4 is a medial side view of the outsole shown in FIG. 2;

FIG. 5 is an expanded sectional view of a portion of the outsole,illustrating a material in accordance with the present disclosuresecured to a backing plate adjacent to a traction element (e.g., acleat);

FIGS. 6-9 are expanded sectional views of the portion of the outsoleshown in FIG. 5, illustrating the soil-shedding performance of theoutsole during a foot strike motion on an unpaved surface;

FIG. 10 is a side cross-sectional view of an outsole in an aspectaccording to the disclosure including a soil-shedding material and soilbeing shed therefrom, during impact with a ground surface;

FIG. 11 is a bottom view of an article of footwear in another aspect ofthe present disclosure having an outsole including a material inaccordance with the present disclosure, the material having discrete andseparate sub-segments;

FIG. 12 is an expanded sectional view of a portion of an outsole inanother aspect of the present disclosure, which includes a material inaccordance with the present disclosure, the material being present in arecessed pocket of an outsole backing plate;

FIG. 13 is an expanded sectional view of a portion of an outsole inanother aspect of the present disclosure, which includes an outsolebacking plate having one or more indentations, and a material inaccordance with the present disclosure, the material being present inand over the indentations;

FIG. 14 is an expanded sectional view of a portion of an outsole inanother aspect of the present disclosure, which includes an outsolebacking plate having one or more indentations having locking members,and a material in accordance with the present disclosure, the materialbeing present in and over the indentations;

FIG. 15 is a bottom view of an article of footwear in another aspect ofthe present disclosure, which illustrates an example golf shoeapplication;

FIG. 16 is a bottom perspective view of an article of footwear inanother aspect of the present disclosure, which illustrates an examplebaseball shoe application;

FIG. 17 is a bottom perspective view of an article of footwear inanother aspect of the present disclosure, which illustrates an exampleAmerican football shoe application;

FIG. 18 is a bottom perspective view of an article of footwear inanother aspect of the present disclosure, which illustrates an examplehiking shoe application; and,

FIGS. 19A and 19B are photographs of articles of footwear with amaterial according to the disclosure after being worn and used duringwet and muddy game conditions, and FIGS. 19C, 19D, 19E, and 19F arephotographs of articles of footwear without a material according to thedisclosure after being worn and used during wet and muddy gameconditions.

The articles of footwear shown in the figures are illustrated for usewith a user's right foot. However, it is understood that the followingdiscussion applies correspondingly to left-footed articles of footwearas well. Further, directional orientations for an article, such as“upward,” “downward,” “top,” “bottom,” “left,” “right,” and the like,are used for ease of discussion, and are not intended to limit the useof the article to any particular orientation.

DESCRIPTION

It has now been discovered that particular materials disposed on aground-facing surface of an outsole of an article of footwear can beeffective at preventing or reducing the accumulation of soil on theoutsole during wear on unpaved surfaces. Accordingly, the presentdisclosure is directed to articles of footwear and footwear components(e.g., footwear outsoles, and the like) at least a portion of which arecomposed of a material comprising an ethylene-alkyl acrylate copolymercomponent consisting of an ethylene-alkyl acrylate copolymer or acombination of two or more ethylene-alkyl acrylate copolymers. Theconcentration of the ethylene-alkyl acrylate copolymer component presentin the material can be from 40 to 80 parts per hundred by weight basedon a total polymer content of the material. As discussed below, it hasbeen found that the inclusion of these materials in articles of footwearand components of footwear can prevent or reduce the accumulation ofsoil on the outsole during wear on unpaved surfaces. Preventing orreducing soil accumulation on the outsole can help preserve tractionduring wear. Preventing or reducing soil accumulation on outsoles duringwear on unpaved surfaces also can significantly affect the weight ofaccumulated soil adhered to the outsole during wear, reducing fatigue tothe wearer caused by the adhered soil.

The terms “article of footwear,” “articles of footwear,” and “footwear”are intended to be used interchangeably to refer to the same article.Typically, the term “article of footwear” will be used in a firstinstance, and the term “footwear” may be subsequently used to refer tothe same article for ease of readability.

As used herein, “ground-facing” is understood to refer to the positionof an element or surface when the element or surface is present on acomponent of an article of footwear or on an article of footwear as thearticle of footwear is conventionally worn on a foot. For example, aground-facing surface or side of an outsole is the side or surface ofthe outsole which faces the ground when the outsole is part of aconventional article of footwear, and the article of footwear is worn ona foot in a conventional manner.

References herein to “soil” include any of a variety of materialscommonly present on a ground or playing surface and which mightotherwise adhere to an outsole or areas adjacent to an outsole such asan exposed midsole of an article of footwear. Soil can include inorganicmaterials such as mud, sand, dirt, and gravel; organic matter such asgrass, turf, leaves, other vegetation, and excrement; combinations ofinorganic and organic materials such as clay; other materials such asground rubber particles, and any combinations thereof. While not wishingto be bound by theory, it is believed that the material as describedherein can exhibit a lower level of adhesion to soil as compared toother materials. In aspects of the present disclosure, the material canprovide compressive compliance when present on an outsole. Additionally,when the material is present in the form of an open-cell foam, theopen-cell foam can take up and expel water. In particular, it isbelieved that the compressive compliance provided by the material, thechemical nature of the material, or both in combination, can disrupt theadhesion of soil on the outsoles and the cohesion of soil particles toeach other. Additionally, when the material is present in the form of anopen-cell foam which takes up water, the expulsion of water from thefoam, alone or in combination with the foam's compressive complianceand/or its chemical nature, can further disrupt the adhesion of soil onthe outsoles and the cohesion of soil particles to each other.

The disruption in the adhesion and/or cohesion of soil are believed tobe mechanisms at least partially responsible for preventing (orotherwise reducing) soil from accumulating on the outsoles—mechanismsachieved due to the presence of the material. As can be appreciated,preventing soil from accumulating on an outsole can improve theperformance of traction elements present on the outsole during wear onunpaved surfaces, can prevent the footwear from gaining weight due toaccumulated soil during wear, can preserve ball handling performance ofthe outsole, and thus can provide significant benefits to a wearer ascompared to an article of footwear without the material present on theoutsole.

In a first aspect, the present disclosure is directed to an outsole foran article of footwear, the outsole comprising: a ground-facing surfaceof the outsole and a surface of the outsole opposing the ground-facingsurface, the opposing surface configured to be secured to an upper foran article of footwear, wherein a material is present on at least aportion of the ground-facing surface of the outsole, the materialcompositionally comprising an ethylene-alkyl acrylate copolymercomponent consisting of an ethylene-alkyl acrylate copolymer or acombination of two or more ethylene-alkyl acrylate copolymers, wherein aconcentration of the ethylene-alkyl acrylate copolymer component presentin the material is from 40 to 80 parts per hundred by weight based on atotal polymer content of the material.

The term “polymer” refers to a molecule having polymerized units of oneor more species of monomer. The term “polymer” is understood to includehomopolymers and copolymers. The term “copolymer” refers to a polymerhaving polymerized units of two or more species of monomer, and isunderstood to include terpolymers or other polymers formed from multipledifferent monomers.

The material of the present disclosure can be present as one or morelayers disposed on, or otherwise affixed to, at least a portion of asurface (e.g., a surface of an outsole of an article of footwear). Insome aspects, the layer(s) is provided as a single continuous segmenton, or affixed to, the surface. Alternatively, the layer(s) is providedin multiple discontinuous segments on, or affixed to, the surface. Thedisposition of the material on the surface is not intended to be limitedby any application process (e.g., extrusion, co-extrusion, injectionmolding, lamination, spray coating, etc.) by which the material isapplied to affixed to the surface.

The material can be present in the form of an open-cell foam. Whenpresent in the form of an open-cell foam, the material can have adensity of greater than 1.5 pounds per cubic foot (lbs./ft.³). Forexample, the density of the material in open-cell foam form can be from1.5 lbs./ft.³ to 2 lbs./ft.³. Further, when present as an open-cellfoam, the material can have an average cell diameter ranging from 0.65millimeters (mm) to 1.4 mm. Still further, when present as an open-cellfoam, the material can have an oil absorption weight capacity of atleast 27 (as determined according to the Oil Absorption Test, describedherein).

The ethylene-alkyl acrylate copolymer component of the material cancomprise or consist essentially of a copolymer of ethylene and methylacrylate, or a copolymer of ethylene and ethyl acrylate, or acombination of both. The ethylene-alkyl acrylate copolymer component cancomprise or consist essentially of an ethylene-alkyl acrylate copolymerhaving an alkyl acrylate content of between 3% and 45% based on a totalweight of the copolymer. The ethylene-alkyl acrylate copolymer componentcan comprise or consist essentially of an ethylene-alkyl acrylatecopolymer having an alkyl acrylate content of between 15% and 25% basedon a total weight of the copolymer. The ethylene-alkyl acrylatecopolymer component can comprise or consist essentially ofethylene-methyl acrylate (EMA), ethylene-ethyl acrylate (EEA), andcombinations thereof. The ethylene-alkyl acrylate copolymer componentcan comprise or consist essentially of ethylene-methyl acrylate (EMA).Alternatively or in addition, the ethylene-alkyl acrylate copolymercomponent can comprise or consist essentially of at least oneethylene-alkyl acrylate copolymer having a melt flow rate of from 0.5grams per ten minutes (g/10 mins.) to 4 g/10 mins., as determinedaccording to ASTM D1238 using a 2160 gram (g) weight and a temperatureof 190° C. (Unless otherwise specified, temperatures referred to hereinare based on atmospheric pressure (i.e. one atmosphere).)

The terms “at least one” and “one or more of” an element are usedinterchangeably, and have the same meaning that includes a singleelement and a plurality of the elements, and may also be represented bythe suffix “(s)” at the end of the element. For example, “at least oneethylene-alkyl acrylate copolymer,” “one or more ethylene-alkyl acrylatecopolymers,” and “ethylene-alkyl acrylate copolymer(s)” may be usedinterchangeably and have the same meaning.

The material can further comprise a polyethylene component. Thepolyethylene component can comprise or consist essentially of at leastone polyethylene having a density of from 0.91 grams per cubiccentimeters (g/cc) to 0.95 g/cc, and a melt flow rate, as determinedaccording to ASTM D1238 using a 2160 g weight and a temperature of 190°C., of from 0.910 g/10 mins. to 0.950 g/10 mins., from 0.917 g/10 mins.to 0.930 g/10 mins., or from 0.917 g/10 mins. to 0.923 g/10 mins.

The material can comprise from 20% to 80% by weight of theethylene-alkyl acrylate copolymer component, and from 20% to 80% byweight of the polyethylene component. The material can comprise from 40%to 60% by weight of the ethylene-alkyl acrylate copolymer component, andfrom 20% to 80% by weight of the polyethylene component. The materialcan comprise from 50% to 60% by weight of the ethylene-alkyl acrylatecopolymer component, and from 20% to 80% by weight of the polyethylenecomponent. The recitations of a numerical range by endpoints include theendpoints and all numbers within that numerical range. For example, aconcentration ranging from 40% by weight to 60% by weight includes 40%by weight, 60% by weight, and all values between 40% by weight and 60%by weight (e.g., 40.1%, 41%, 45%, 50%, 52.5%, 55%, 59%, etc.).Additionally, as used herein, a reference to a material, element, etc.having a value of a property within a range is generally understood tomean that the property has a single value which is encompassed withinthe described range.

References to “a” chemical compound refers one or more molecules of thechemical compound, rather than being limited to a single molecule of thechemical compound. Furthermore, the one or more molecules may or may notbe identical, so long as they fall under the category of the chemicalcompound. Thus, for example, “a” polyethylene or polyethylene componentis interpreted to include one or more polymer molecules of thepolyethylene, where the polymer molecules may or may not be identical(e.g., different molecular weights and/or isomers).

At least a portion of the polymer component of the material can becrosslinked. For example, the ethylene-alkyl acrylate component can becrosslinked to itself. When present, a polyester component can becrosslinked to itself. Alternatively or in addition, when present, atleast a portion of the polyester component can be crosslinked to atleast a portion of the ethylene-alkyl acrylate component. When present,at least a portion of an elastomer can be crosslinked to itself.Alternatively or in addition, when present, at least a portion of theelastomer can be crosslinked to at least a portion of the ethylene-alkylacrylate component.

The outsole of the present disclosure can be an outsole wherein thematerial exhibits an impact energy of from 0 Joules to 0.6 Joules, asdetermined according to the Impact Energy Test disclosed herein.Alternatively or in addition, an article of footwear containing theoutsole can be an article that, after running in the article on a wet ordamp soil surface, has at least 10% less soil by weight adhered to itsoutsole as compared to a second article of footwear that is identicalexcept that it does not include an outsole having the material.

In a second aspect, the present disclosure is also directed to anarticle of footwear, the article comprising: an outsole having a firstsurface at least partially secured to the upper and an opposing secondsurface, wherein a material is present on at least a portion of thesecond surface, the material compositionally comprising anethylene-alkyl acrylate copolymer component consisting of anethylene-alkyl acrylate copolymer or a combination of two or moreethylene-alkyl acrylate copolymers, wherein a concentration of theethylene-alkyl acrylate copolymer component present in the material isfrom 40 to 80 parts per hundred by weight based on a total polymercontent of the material.

The second surface of the outsole can be the ground-facing surface ofthe outsole. The article of footwear can further comprise a plurality ofcleats, wherein a portion of the plurality of cleats are integrallyformed with the second surface of the outsole, are separately formedfrom the second surface of the outsole and permanently attached to thesecond surface of the outsole, are separately formed from the secondsurface of the outsole and are removably attached to the second surfaceof the outsole, or combinations thereof. The article of footwear canfurther comprise a midsole disposed at least partially between the upperand the first surface of the outsole, wherein the first surface of theoutsole is operably secured to the upper with the midsole. The term“operably secured to,” such as for an outsole that is operably securedto an upper, refers collectively to direct connections, indirectconnections, integral formations, and combinations thereof. Forinstance, for an outsole that is operably secured to an upper, theoutsole can be directly connected to the upper (e.g., with an adhesive),the outsole can be indirectly connected to the upper (e.g., with anintermediate midsole), can be integrally formed with the upper (e.g., asa unitary component), and combinations thereof.

In a third aspect, the present disclosure is directed to a method ofmanufacturing an article of footwear, comprising: providing an outsole,the outsole having a first surface and an opposing ground-facingsurface, a material present on the ground-facing surface of the outsole,the material compositionally comprising an ethylene-alkyl acrylatecopolymer component consisting of an ethylene-alkyl acrylate copolymeror a combination of two or more ethylene-alkyl acrylate copolymers,wherein a concentration of the ethylene-alkyl acrylate copolymercomponent present in the material is from 40 to 80 parts per hundred byweight based on a total polymer content of the material; providing anupper; and, securing the upper to at least a portion of the firstsurface of outsole. The step of securing the material can comprise stockfitting the material to the ground-facing surface of the outsole, forexample, such that the material defines an external surface of theoutsole. The step of providing an outsole can comprise forming at leasta portion of the outsole from a second material, and the step ofsecuring the material can comprise thermoforming the material andsecuring the material to the ground-facing surface of the outsole. Theterm “providing,” such as for “providing an outsole,” when recited inthe claims, is not intended to require any particular delivery orreceipt of the provided item. Rather, the term “providing” is merelyused to recite items that will be referred to in subsequent elements ofthe claim(s), for purposes of clarity and ease of readability.

In a fourth aspect, the present disclosure is directed to an article offootwear, the article comprising: an outsole having a ground-facingsurface, an open-cell foam material secured to at least a portion of theground-facing surface, wherein the open-cell foam material has anaverage cell diameter ranging from 0.65 millimeter (mm) to 1.4 mm; andan upper secured to the outsole; wherein the article of footwearprevents or reduces soil accumulation on the outsole such that thearticle of footwear retains at least 10% less soil by weight as comparedto a second article of footwear which is identical to the article offootwear except that the second article of footwear is free of theopen-cell foam material. The article can be an article wherein theoutsole further comprises a plurality of cleats. The article can be anarticle wherein the material is not present on or in direct contact withthe plurality of cleats. The article can be an article wherein a sampleof the outsole obtained in accordance with the Footwear SamplingProcedure exhibits an impact energy of from 0 Joules to 0.6 Joules, asdetermined according to the Impact Energy Test. The article can be anarticle wherein the open-cell foam material comprises an ethylene-alkylacrylate copolymer component consisting of an ethylene-alkyl acrylatecopolymer or a combination of two or more ethylene-alkyl acrylatecopolymers. The article can be an article wherein a concentration of theethylene-acrylate copolymer component present in the open-cell foam isfrom 40 to 80 parts per hundred by weight based on a total polymercontent of the open-cell foam. The article can be an article whereinethylene-alkyl acrylate copolymer component comprises a copolymer ofethylene and methyl acrylate, or a copolymer of ethylene and ethylacrylate, or a combination of both. The article can be an articlewherein the ethylene-alkyl acrylate copolymer component comprises anethylene-alkyl acrylate copolymer having an alkyl acrylate content ofbetween 3% and 45%, based on a total weight of the copolymer.

The article can be an article wherein a sample of the open-cell foammaterial obtained in accordance with the Footwear Sampling Procedure orthe Neat Material Sampling Procedure has an absorption weight capacityof SAE 10W-30 oil of at least 27 times its weight of the open-cell foammaterial, as determined according to the Oil Absorption Test. Thearticle can be an article wherein the open-cell foam material has a meltflow rate in a range of between about 0.5 g/10 mins. and about 100grams/10 mins., as determined according to ASTM D1238 using a 2160 gweight and a temperature of 190° C. The article can be an articlewherein the open-cell foam material has a thickness in a dry state ofabout 0.1 mm to about 12 mm. The article can be an article wherein theopen-cell foam material has a tensile strength of 75 kiloPascals (kPa)to 250 kPa, as determined according to ASTM D882. The article can be anarticle wherein the open-cell foam material has a Young's modulus offrom 0.4 megaPascals (MPa) to 2.5 MPa.

In a fifth aspect, the present disclosure is directed to a method of useof an article of footwear, the method comprising: providing an articleof footwear comprising an outsole having a ground-facing surface, anopen-cell foam material secured to at least a portion of theground-facing surface, wherein the open-cell foam material has anaverage cell diameter ranging from 0.65 mm to 1.4 mm; and wearing thearticle of footwear under conditions in which the outsole comes intodirect contact with wet soil, wherein the article of footwear preventsor reduces accumulation of the soil on the outsole such that the articleof footwear retains at least 20% less soil by weight as compared to asecond article of footwear worn under identical conditions wherein thesecond article of footwear is identical to the article of footwearexcept that the second article of footwear is free of the open-cell foammaterial. The method can be a method wherein the outsole furthercomprises a plurality of cleats. The method can be a method wherein theopen-cell foam is not present on or in direct contact with the pluralityof cleats. The method can be a method wherein a sample of the outsoleobtained in accordance with the Footwear Sampling Procedure exhibits animpact energy of from 0 Joules to 0.6 Joules, as determined according tothe Impact Energy Test. The method can be a method wherein a sample ofthe outsole obtained in accordance with the Footwear Sampling Procedureexhibits an impact energy of from 0.2 Joules to 0.4 Joules, asdetermined according to the Impact Energy Test. The method can be amethod wherein the open-cell foam material comprises an ethylene-alkylacrylate copolymer component consisting of an ethylene-alkyl acrylatecopolymer or a combination of two or more ethylene-alkyl acrylatecopolymers. The method can be a method wherein a concentration of theethylene-acrylate copolymer component present in the open-cell foammaterial is from 40 to 80 parts per hundred by weight based on a totalpolymer content of the open-cell foam material.

The article of footwear of the present disclosure may be designed for avariety of uses, such as sporting, athletic, military, work-related,recreational, or casual use. Primarily, the article of footwear isintended for outdoor use on unpaved surfaces (in part or in whole), suchas on a ground surface including one or more of grass, turf, gravel,sand, dirt, clay, mud, and the like, whether as an athletic performancesurface or as a general outdoor surface. However, the article offootwear may also be desirable for indoor applications, such as indoorsports including dirt playing surfaces for example (e.g., indoorbaseball fields with dirt infields). In preferred aspects, the articleof footwear is designed for use in outdoor sporting activities, such asglobal football/soccer, golf, American football, rugby, baseball,running, track and field, cycling (e.g., road cycling and mountainbiking), and the like. The terms “preferred” and “preferably” refer toaspects of the invention that may afford certain benefits, under certaincircumstances. However, other aspects may also be preferred, under thesame or other circumstances. Furthermore, the recitation of one or morepreferred aspects does not imply that other aspects are not useful, andis not intended to exclude other aspects from the scope of the presentdisclosure.

The article of footwear optionally includes traction elements (e.g.,lugs, cleats, studs, spikes, fins, blades, and the like) to providetraction on soft and slippery surfaces. Traction elements are commonlyincluded in footwear designed for use in sports such as globalfootball/soccer, golf, American football, rugby, baseball, and the like,which are frequently played on unpaved surfaces. Lugs and/or exaggeratedtread patterns are commonly included in footwear including shoes andboots design for use under rugged outdoor conditions, such as trailrunning, hiking, and military use.

FIGS. 1-4 illustrate an example article of footwear of the presentdisclosure, referred to as an article of footwear 100, and which isdepicted as footwear for use in global football/soccer applications. Asshown in FIG. 1, the footwear 100 includes an upper 110 and an outsole112 as footwear article components, where outsole 112 includes aplurality of traction elements 114 (e.g., cleats) and a material 116secured to the outsole 112 at an external or ground-facing side of theoutsole 112. While many of the footwear of the present disclosurepreferably include traction elements such as cleats, it is to beunderstood that in other aspects, the incorporation of cleats isoptional.

The upper 110 of the footwear 100 has a body 118 which may be fabricatedfrom materials known in the art for making articles of footwear, and isconfigured to receive a user's foot. For example, the upper body 118 maybe made from or include one or more components made from one or more ofnatural leather; a knit, braided, woven, or non-woven textile made inwhole or in part of a natural fiber; a knit, braided, woven or non-woventextile made in whole or in part of a synthetic polymer or a syntheticpolymer film; and combinations thereof. The upper 110 and components ofthe upper 110 may be manufactured according to conventional techniques(e.g., molding, extrusion, thermoforming, stitching, knitting). Whileillustrated in FIG. 1 with a generic design, the upper 110 mayalternatively have any desired aesthetic design, functional design,brand designators, and the like.

The outsole 112 may be directly or otherwise operably secured to theupper 110 using any suitable mechanism or method. For example, the upper110 may be stitched to the outsole 112, or the upper 110 may be glued tothe outsole 112, such as at or near a bite line 120 of the upper 110.The footwear 100 can further include a midsole (not shown) securedbetween the upper 110 and the outsole 112, or can be enclosed by theoutsole 112. When a midsole is present, the upper 110 may be stitched,glued, or otherwise attached to the midsole at any suitable location,such as at or below the bite line 120.

As further shown in FIGS. 1 and 2, the layout of outsole 112 can besegregated into a forefoot region 122, a midfoot region 124, and a heelregion 126. The forefoot region 122 is disposed proximate a wearer'sforefoot, the midfoot region 124 is disposed between the forefoot region122 and the heel region 126, and the heel region 126 is disposedproximate a wearer's heel and opposite the forefoot region 122. Theoutsole 112 may also include a forward edge 128 at the forefoot region122 and a rearward edge 130 at the heel region 126. In addition to theselongitudinal designations, the left/right sides of outsole 112 can alsobe respectively designated by a medial side 132 and a lateral side 134.Each of these designations can also apply to the upper 110 and moregenerally to the footwear 100, and are not intended to particularlydefine structures or boundaries of the footwear 100, the upper 110, orthe outsole 112.

The outsole 112 can optionally include a backing plate 136, which, inthe shown example, extends across the forefoot region 122, the midfootregion 124, and the heel region 126. The backing plate 136 is an examplebacking plate member or outsole backing member for use in an article offootwear, and can provide structural integrity to the outsole 112.However, the backing plate 136 can also be flexible enough, at least inparticular locations, to conform to the flexion of a wearer's footduring the dynamic motions produced during wear. For example, as shownin FIGS. 1 and 2, the backing plate 136 may include a flex region 138 atthe forefoot region 122, which can facilitates flexion of the wearer'stoes relative to the foot in active use of the footwear 100.

The optional backing plate 136 may have a top (or first) surface 142(best shown in FIGS. 3 and 4), a bottom (or second) surface 144, and asidewall 146, where the sidewall 146 can extend around the perimeter ofthe backing plate 136 at the forward edge 128, the rearward edge 130,the medial side 132, and the lateral side 134. The top surface 142 isthe region of the backing plate 136 (and the outsole 112 more generally)that may be in contact with and operably secured to the upper 110 and/orto any present midsole or insole.

The bottom surface 144 is a ground-facing surface of the backing plate136 that is covered (or at least partially covered) by the material 116,and would otherwise be configured to contact a ground surface, whetherindoors or outdoors, if the material 116 were otherwise omitted. Thebottom surface 144 is also the portion of outsole 112 that the fractionelements 114 can extend from, as discussed below.

The optional backing plate 136 can be manufactured with one or morelayers, may be produced from any suitable material(s), and can provide agood interfacial bond to the material 116, as discussed below. Examplesof suitable materials for the backing plate 136 include one or more ofthermoplastic elastomers, thermoset polymers, elastomeric polymers,silicone polymers, natural and synthetic rubbers, composite materials(including polymers reinforced with carbon fiber and/or glass), naturalleather, and metals (such as aluminum, steel and the like).

In particular aspects, the optional backing plate 136 is manufacturedfrom one or more polymers having similar chemistries to the polymers ofthe material 116. In other words, the backing plate and the materialdisclosed herein can both comprise or consist essentially of polymershaving the same or similar functional groups, and/or can both compriseor consist essentially of polymers having the same or similar levels ofpolarity, or can both comprise or consist essentially of thermopolymers,or combinations thereof. For example, the backing plate and the materialcan both comprise or consist essentially of one or more ethyl-alkylcopolymers, one or more polyolefins (e.g., thermoplastic polyolefins),or the like. The backing plate and the material can both comprise orconsist essentially of thermopolymers having levels of polarity within20% of each other, or within 10% of each other. The types of similarpolymers can be beneficial for improving manufacturing compatibilitiesbetween the material 116 and the backing plate 136, and also forimproving the interfacial bond strength between the polymers.Alternatively, one or more tie layers (not shown) can be applied betweenthe backing plate 136 and the material 116 in order to improve theirinterlayer bonding.

The traction elements 114 may each include any suitable cleat, stud,spike, lug, fin, blade, or similar element configured to enhancetraction for a wearer during cutting, turning, stopping, accelerating,and backward movement. The traction elements 114 can be arranged in anysuitable pattern along the bottom surface 144 of the backing plate 136.For instance, the traction elements 114 can be distributed in groups orclusters along the outsole 112 (e.g., clusters of 2-8 traction elements114). As best shown in FIGS. 1 and 2, the traction elements 114 can begrouped into a cluster 147A at the forefoot region 122, a cluster 147Bat the midfoot region 124, and a cluster 147C at the heel region 126. Inthis example, six of the traction elements 114 are substantially alignedalong the medial side 132 of the outsole 112, and the other six tractionelements 114 are substantially aligned along the lateral side 134 of theoutsole 112.

The traction elements 114 may alternatively be arranged along theoutsole 112 symmetrically or non-symmetrically between the medial side132 and the lateral side 134, as desired. Moreover, one or more of thetraction elements 114 may be arranged along a centerline of outsole 112between the medial side 132 and the lateral side 134, such as a blade114A, as desired to enhance or otherwise modify performance.

Alternatively (or additionally), traction elements can also include oneor more front-edge traction elements 114, such as one or more blades114B, one or more fins 114C, and/or one or more cleats (not shown)operably secured to (e.g., integrally formed with) the backing plate 136at a front-edge region between forefoot region 122 and cluster 147A. Inthis application, the material 116 can optionally extend across thebottom surface 144 at this front-edge region while maintaining goodtraction performance.

Furthermore, the traction elements 114 may each independently have anysuitable dimension (e.g., shape and size). For instance, in somedesigns, each traction element 114 within a given cluster (e.g.,clusters 147A, 147B, and 147C) may have the same or substantially thesame dimensions, and/or each traction element 114 across the entirety ofthe outsole 112 may have the same or substantially the same dimensions.Alternatively, the traction elements 114 within each cluster may havedifferent dimensions, and/or each fraction element 114 across theentirety of the outsole 112 may have different dimensions.

Examples of suitable shapes for the traction elements 114 includerectangular, hexagonal, cylindrical, conical, circular, square,triangular, trapezoidal, diamond, ovoid, as well as other regular orirregular shapes (e.g., curved lines, C-shapes, etc. . . . ). Thetraction elements 114 may also have the same or different heights,widths, and/or thicknesses as each other, as further discussed below.Further examples of suitable dimensions for the traction elements 114and their arrangements along the backing plate 136 include thoseprovided in soccer/global football footwear commercially available underthe tradenames “TIEMPO,” “HYPERVENOM,” “MAGISTA,” and “MERCURIAL” fromNike, Inc. of Beaverton, Oreg.

The traction elements 114 may be incorporated into the outsole oroptional backing plate 136 of the outsole by any suitable mechanism suchthat the traction elements 114 preferably extend from the bottom surface144. For example, as discussed below, the fraction elements 114 may beintegrally formed with the backing plate 136 through a molding process.Alternatively, the outsole or optional backing plate 136 may beconfigured to receive removable traction elements 114, such as screw-inor snap-in traction elements 114. In these aspects, the backing plate136 may include receiving holes (e.g., threaded or snap-fit holes, notshown), and the traction elements 114 can be screwed or snapped into thereceiving holes to secure the traction elements 114 to the outsole orbacking plate 136. In some applications, the receiving holes may beraised or otherwise protrude from the general plane of the bottomsurface 144 of the outsole or backing plate 136 (e.g., for soft ground(SG) footwear). Alternatively, the receiving holes may be flush with thebottom surface 144.

In further examples, a first portion of the traction elements 114 can beintegrally formed with the outsole or optional backing plate 136 and asecond portion of the traction elements 114 can be secured withscrew-in, snap-in, or other similar mechanisms (e.g., for SG profootwear). The fraction elements 114 may also be configured as shortstuds for use with artificial ground (AG) footwear, if desired. In someapplications, the receiving holes may be raised or otherwise protrudefrom the general plane of the bottom surface 144 of the backing plate136. Alternatively, the receiving holes may be flush with the bottomsurface 144.

The traction elements 114 can be fabricated from any suitable materialfor use with the outsole 112 or optional backing plate 136. For example,the traction elements 114 may include one or more of thermoplasticelastomers, thermoset polymers, elastomeric polymers, silicone polymers,natural and synthetic rubbers, composite materials (including polymersreinforced with carbon fiber and/or glass), natural leather, and metals(such as aluminum, steel and the like). In aspects in which the tractionelements 114 are integrally formed with the outsole or backing plate 112(e.g., molded together), the fraction elements 114 preferably includethe same materials as the outsole or backing plate 112 (e.g.,thermoplastic elastomers). Alternatively, in aspects in which thetraction elements 114 are separate and insertable into receiving holesof the backing plate 112, the traction elements 114 can include anysuitable materials that can be secured in the receiving holes of theoutsole or backing plate 112 (e.g., metals and thermoplasticelastomers).

The optional backing plate 136 (and more generally, the outsole 112) mayalso include other features other than the traction elements 114 thatcan provide support or flexibility to the outsole and/or for aestheticdesign purposes. For instance, the backing plate 136 may also includeridges 148 that may be raised or otherwise protrude from the generalplane of the bottom surface 144. As shown, ridges 148 can extend alongthe arrangement pathways of the traction elements 114, if desired. Thesefeatures (e.g., ridges 148) can be integrally formed into the backingplate 136, or alternatively, be removable features that are securable tothe backing plate 136. Suitable materials for these features includethose discussed above for the traction elements 114.

The optional backing plate 136 (and more generally, the outsole 112) mayalso include other features such as exaggerated tread patterns, lugs,and the like, which are configured to contact the ground or playingsurface to increase fraction, to enhance performance, or for aestheticdesign purposes. These other features can be present on the outsole inplace of or in addition to the traction elements 114, and can be formedfrom the suitable materials discussed above for the traction elements114.

As further shown in FIGS. 3 and 4, the traction elements 114 can bearranged such that when footwear 100 rests on a flat surface 149, theground-facing surface 144 of the outsole or optional backing plate 136and the material 116 are offset from the flat surface 149. As such, thetraction elements 114 can receive the greatest levels of shear andabrasive contact with surfaces during use, such as by digging into soilduring cutting, turning, stopping, accelerating, backward movements, andthe like. In comparison, the material 116 at its offset location canremain partially protected from a significant portion of these shear andabrasive conditions, thereby preserving its integrity during use.

FIG. 5 is an expanded sectional view of the material 116 and theground-facing surface 144 of the outsole or backing plate 136 at one ofthe traction elements 114. In this shown example, the traction element114, which can be representative of one or more of the other tractionelements 114, is integrally molded with the backing plate 136 andincludes a shaft 150 that protrudes downward beyond the ground-facingsurface 144 and the material 116. The shaft 150 itself may include anouter side surface 152 and a terminal edge 154. The terminal edge 154 ofthe shaft 150 is the distal end of the traction element 114, oppositefrom the ground-facing surface 144, and is the portion of the tractionelement 114 that can initially contact and penetrate into a playing orground surface.

As mentioned above, the traction element 114 may have any suitabledimensions and shape, where the shaft 150 (and the outer side surface152) can correspondingly have rectangular, hexagonal, cylindrical,conical, circular, square, triangular, trapezoidal, diamond, ovoid, aswell as other regular or irregular shapes (e.g., curved lines, C-shapes,etc. . . . ). Similarly, the terminal edge 154 can have dimensions andsizes that correspond to those of the outer side surface 152, and can besubstantially flat, sloped, rounded, and the like. Furthermore, in someaspects, the terminal edge 154 can be substantially parallel to thebottom surface 144 and/or the material 114.

Examples of suitable average lengths 156 for each shaft 150 relative tobottom surface 144 range from 1 mm to 5 mm, from 5 mm to 10 mm or from10 mm to 15 mm, where, as mentioned above, each traction element 114 canhave different dimensions and sizes (i.e., the shafts 150 of the varioustraction elements 114 can have different lengths).

In the example shown in FIGS. 1-5, the material 116 is present on theentire ground-facing surface 144 of the backing plate 136 (or outsole)between (but not including) the traction elements 114. For instance, asshown in FIG. 5, the material 116 can cover the ground-facing surface144 at locations around the shaft 150 of each traction element 114, suchthat material 116 does not cover the outer side surface 152 or theterminal edge 154 of the traction element 114, other than optionally ata base region 158 of the shaft 150. This can preserve the integrity ofthe material 116 and preserve traction performance of the tractionelements 114. In some aspects, the material 116 does not cover orcontact any portion of the outer side surface 152 of the shaft 150. Inother aspects, the base region 158 that the material 116 covers andcontacts the outer side surface 152 is less than 25%, less than 15%, orless than 10% of the length of the shaft 150, as an average distancemeasured from the bottom surface 144 at the traction element 114.

As can be seen in FIG. 5, the material 116 can be present as a thinlayer (thin relative to the length of the shaft of the traction element114) to minimize or otherwise reduce its impact on the traction elements114. Examples of suitable average thicknesses for the material 116 rangefrom about 0.0025 mm, about 0.025 mm, or about 0.1 mm to about 0.15 mm,about 0.25 mm, about 0.35 mm, about 0.5 mm, about 1.0 mm, about 5.0 mm,or about 12 mm. The terms “about” and “substantially” are used hereinwith respect to measurable values and ranges due to expected variationsknown to those skilled in the art (e.g., limitations and variability inmeasurements). The thickness of the layer of the material 116 as presenton the outsole can range from about 0.1 mm to about 12 mm, or from about0.5 mm to about 10 mm, or from about 1 mm to about 7 mm. As depicted,the thicknesses for the material 116 are measured between theinterfacial bond at the bottom surface 144 of the backing plate 136 andan exterior surface of the material 116 (referred to as a materialsurface 162).

In some alternative aspects, the material 116 can also (oralternatively) be present on one or more regions of the tractionelements 114. This can be beneficial, for example, in applications wherethe traction element 114 has a central base with multiple shafts 150that protrude from the periphery of the central base, such as is foundon some types of spikes used on golf shoes. In such aspects, thematerial 116 can be present on at least the central base of the tractionelement 114. For example, when the multiple shafts 150 of the fractionelement are configured to be ground-contacting during wear, but thecentral base of the traction element is ground-facing but not configuredto be ground-contacting during wear, the material 116 can be present ononly the central base of the traction element, and not on the multipleshafts 150 of the traction elements. Furthermore, for some applications,the material 116 may also cover the entirety of one or more of thetraction elements 114 (e.g., on the shaft 150). Alternatively, thetraction elements 114 can be free of the material.

The presence of the material 116 on the ground-facing side of outsole112 (i.e., on bottom surface 144) allows the material 116 to come intocontact with soil (e.g., mud) during use, which is believed to enhancethe soil-shedding performance for the footwear 100, as explained herein.However, the material 116 can also optionally be present on one or morelocations of the sidewall 146 of the outsole or backing plate 136, onone or more locations of an included midsole (not shown), on one or morelocations on the upper 110, and combinations thereof.

In some aspects, when the material is present in the form of anopen-cell foam, the material 116 can take up water that is in contactwith the material 116. For instance, the material 116 may take up waterfrom mud, wetted soil, and wet grass, such as during a warm up prior toa competitive match, as well as during a competitive match. The terms“take up,” “taking up,” “uptake,” “uptaking,” “absorb”, “re-absorb” andthe like means the material can draw a liquid (e.g., water) from anexternal source, such as by absorption, adsorption, capillary action,and combinations thereof. Furthermore, the term “water” refers to anaqueous liquid that can be pure water, or can be an aqueous carrier withlesser amounts of dissolved, dispersed or otherwise suspended materials(e.g., particulates, other liquids, and the like).

The amount of water that the material 116 can take up depends on avariety of factors, such as its composition (e.g., its relativehydrophobicity or hydrophilicity), its cross-linking density, itsthickness, and its interfacial bond to the backing plate 136. Inaddition, the presence of larger pore sizes on the surface of anopen-cell foam can increase the amount of surface water available. Thiscan be achieved through foam processing parameters (e.g., the amount ofblowing agent, processing temperature or pressure) or throughpost-processing (e.g., roll milling or needle puncturing.).

Foams of low density are highly compliant and compressible. The term“compliant” refers to the stiffness of a material, and can be determinedby Young's modulus. The lower the degree of crosslinking in a material,or the greater the distance between crosslinks in a material, the morecompliant the material. In addition, the use of an open-cell foam (asmaterial 116, for example) allows for macroscopic uptake of water intothe surface pores. The compliance, and surface water, and water presentin the pores of the open-cell foam accordingly can allow the material116, when in open-cell foam form, to readily compress under an appliedpressure (e.g., during a foot strike on the ground), which compressioncan quickly expel at least a portion of its retained water (depending onthe extent of compression). While not wishing to be bound by theory, itis believed that this combination of compressive compliance and waterexpulsion can disrupt the adhesion and cohesion of soil at outsole 112,which prevents or otherwise reduces the accumulation of soil on outsole112.

In addition to expelling water, the compressed material 116, whenpresent in the form of an open-cell foam, may also re-absorb water whenthe compression is released (e.g., liftoff from a foot strike duringnormal use). As such, during use in a moisture-containing environment(e.g., a muddy or wet ground), the material 116, when present in theform of an open-cell foam, can be dynamically expelling and re-absorbingwater over successive foot strikes. This can accordingly allow theopen-cell foam material 116 to continue to prevent soil accumulationover extended periods of time (e.g., during an entire competitive match)so long as there is ground water available for re-absorption.

FIGS. 6 to 9 illustrate an example method of using footwear 100 with amuddy or wet ground 166, which depict the believed mechanism forpreventing soil accumulation on the outsole 112. It is known that thesoil of the ground 166 can accumulate on an outsole (e.g., between thetraction elements) during normal athletic or casual use, in particularwhen the ground 166 is wet. The soil is believed to accumulate on theoutsole due to a combination of adhesion of the soil particles to thesurface of the outsole and cohesion of the soil particles to each other.In order to break these adhesive/cohesive forces, the soil particlesneed to be subjected to stresses high enough to exceed theiradhesive/cohesive activation energies. When this is achieved, the soilparticles can then move or flow under the applied stresses, whichdislodge or otherwise shed portions of the soil from the outsole.

However, during typical use of conventional cleated footwear, such asduring competitive sporting events (e.g., global football/soccermatches, golfing events, and American football games), the actions ofwalking and running are not always sufficient to dislodge the soil fromthe outsole. This can result in the soil sticking to the outsoles,particularly in the interstitial regions between the individual tractionelements. As can be appreciated, this soil can quickly accumulate toincrease the weight of the footwear and reduce the effectiveness of thefraction elements (e.g., because they have less axial or normal extentcapable of engaging with the ground 166), each of which can have asignificant impact on athletic performance.

The incorporation of the (polymeric) material 116 to the outsole 112,however, is believed to disrupt the adhesion and cohesion of soil at theoutsole 112, thereby reducing the adhesive/cohesive activation energiesotherwise required to induce the flow of the soil particles. As shown inFIG. 6, when the material is in the form of an open-cell foam, thefootwear 100 can be provided in a pre-conditioned state where water ispresent in the open-cells of the foam material 116. This can beaccomplished in a variety of manners, such as spraying the outsole 112with water, soaking the outsole 112 in water, or otherwise exposing thematerial 116 to water in a sufficient amount for a sufficient duration.Alternatively (or additionally), when water or wet materials are presenton the ground 166, footwear 100 can be used in a conventional manner onthe ground 166 until the material 116 takes up a sufficient amount ofwater from the ground 166 or wet materials to reach its pre-conditionedstate.

During a foot strike, the downward motion of the footwear 100(illustrated by arrow 168) causes the fraction element 114 to contactthe ground 166. As shown in FIG. 7, the continued applied pressure ofthe foot strike can cause the traction element 114 to penetrate into thesofter soil of the ground 166 until the material surface 162 of thematerial 116 contacts the ground 166. As shown in FIG. 8, furtherapplied pressure of the foot strike can press the material 116 into theground 166, thereby at least partially compressing the material 116under the applied pressure (illustrated by arrows 170). As can be seen,this compression of the material 116 into the soil of the ground 166typically compacts the soil, increasing the potential for the soilparticles to adhere to outsole 112 and to cohesively adhere to eachother (clumping together).

As shown in FIG. 9, when the footwear 100 is lifted following the footstrike (illustrated by arrow 174), it is believed that the compressionapplied to the material 116 is released, and so the material 116 can befree to expand to its pre-compression thickness. In some examples, ithas been found that, when the outsole 112 is lifted apart from theground 166, a thin water layer can remain in contact with the materialsurface 162, which can be taken back up into the open-cell foam material116. This re-uptake of water from the open-cell foam material surface162 (after compression is removed (e.g., within about 1, 2, or 5seconds)) can be taken back into the open-cell foam material 116.

This cyclic compression and expansion from repeated, rapid, and/orforceful foot strikes during use of the footwear 100 can alsomechanically disrupt the adhesion of any soil still adhered to thematerial surface 162, despite the presence of the material 116 in arelatively thin layer. In particular, the increased compliance isbelieved, under some conditions, to lead to inhomogeneous shear statesin the soil when compressed in the normal or vertical direction, whichcan also lead to increased interfacial shear stresses and a decrease insoil accumulation.

In addition to the absorption, compression, and reabsorption cyclediscussed above, the compliance of the material 116, for exampleelongational compliance in the longitudinal direction, may allow thematerial 116 to be malleable and stretchable. For example, asillustrated in FIG. 10, during a foot rotation in a foot strike (e.g.,as the foot generally rolls from heel to toe during a stride), theoutsole 112 and the material 116 are correspondingly flexed (e.g.,inducing compression forces illustrated by arrows 170).

The increased elongation or stretchiness of the material 116 canincrease the extent that the material 116 stretches during this flexing,which can induce additional shear on any soil adhered to the materialsurface 162. As illustrated, a rolling ground strike creates a curvedoutsole 112 and curved compressed layer of the material 116, with thewater being expelled therefrom (when present as an open-cell foam) andtransverse material 116 stretching forces being induced to pull apartand shed the soil. The compression forces (illustrated by arrows 170) onthe material 116, which can help to expel the water (when the materialis present as an open-cell foam) are particularly strong at points ofcontact with the ground 166 and/or where the radius of curvature of thecurved outsole 112/curved material 116 is relatively small or at itsminimum, and so the inclusion of the material 116 in these locations canhelp to keep at least these portions of the outsole clear of soil duringwear.

In addition to being effective at preventing soil accumulation on theoutsole, the material 116 has also been found to be sufficiently durablefor its intended use on the ground-contacting side of the outsole 112.Durability is based on the nature and strength of the interfacial bondof the material 116 to the bottom surface 144 of the backing plate 136,as well as the physical properties of the material 116 itself. For manyexamples, during the useful life of the outsoles and/or articles offootwear, the material 116 will not delaminate from the backing plate136, and it is substantially abrasion- and wear-resistant (e.g.,maintaining its structural integrity without rupturing or tearing). Invarious aspects, the useful life of the material 116 (and the outsole112 and footwear 100 containing it) is at least 10 hours, 20 hours, 50hours, 100 hours, 150 hours, or 200 hours of wear. For example, theuseful lifetime of the material 116 can be from 10 hours to 200 hours ofwear. In other applications, the useful lifetime of the material 116 canbe from 20 hours to 150 hours of wear. In further applications, theuseful lifetime of the material can be from 50 to 150 hours of wear. Inmany aspects, the outsoles and articles of footwear of the presentdisclosure retain their soil-shedding ability for the useful lifetime.

While the material 116 is illustrated above in FIGS. 1-4 as extendingacross the entire bottom surface 144 of the outsole 112 of the footwear100, in alternative aspects, the material 116 can alternatively bepresent as one or more segments that are present at separate, discretelocations on the bottom surface 144 of the outsole 112. For instance, asshown in FIG. 11, the material 116 can alternatively be present as afirst segment 116A secured to the bottom surface 144 at the forefootregion 122, such as in the interstitial region between the tractionelements 114 of cluster 147A; a second segment 116B secured to thebottom surface 144 at the midfoot region 124, such as in theinterstitial region between the fraction elements 114 of cluster 147B;and/or a third segment 116C secured to the bottom surface 144 at theheel region 126, such as in the interstitial region between the fractionelements 114 of cluster 147C. In each of these examples, the remainingregions of the bottom surface 144 can be free of the material 116.

In some arrangements, the material 116 may include one or more segmentssecured to the bottom surface 144 at a region 178 between the clusters147A and 147B, at a region 180 between the clusters 147B and 147C, orboth. For example, the material 116 may include a first segment presenton the bottom surface 144 that encompasses the locations of segment116A, the region 178, and segment 116B as well at the location of region178; and a second segment corresponding to the segment 116B (at thecluster 147C). As also shown in FIG. 11, the segments of the material116 (e.g., segments 116A, 116B, and 116C) can optionally have surfacedimensions that conform to the overall geometry of the backing plate136, such as to conform to the contours of the ridges 148, the fractionelements 114, and the like.

In another arrangement, the bottom surface 144 may include a front edgeregion 182 between the front edge 128 and the cluster 147A (andoptionally include a front portion of the cluster 147A) that is free ofthe material 116. For some uses, soil accumulation is typically mostprominent in the interstitial regions of the clusters 147A, 147B, and147C, in comparison to the front edge 128.

Furthermore, the backing plate 136 can also include one or more recessedpockets, such as a pocket 188 shown in FIG. 12, in which the material116 or a sub-segment of the material 116 can reside. This canpotentially increase the durability of the material 116 by protecting itfrom lateral delamination stresses. For instance, the backing plate 136can include a pocket 188 in the interstitial region of cluster 147C,where the sub-segment 116C of the material 116 can be secured to thebottom surface 144 within the pocket 188. In this case, the dry-statethickness 160 of the material 116 can vary relative to a depth 190 ofthe pocket 188.

In some aspects, the depth 190 of the pocket 188 can range from 80% to120%, from 90% to 110%, or from 95% to 105% of the dry-state thickness160 of the material 116. Moreover, in aspects in which the backing plate136 includes multiple pockets 188, each pocket 188 may have the samedepth 190 or the depths 190 may independently vary as desired. FIG. 13illustrates an alternative design for the engagement between thematerial 116 and the bottom surface 144. In this case, the backing plate136 can include one or more recessed indentations 192 having anysuitable pattern(s), and in which portions of the material 116 extendinto the indentations 192 to increase the interfacial bond surface areabetween the material 116 and the bottom surface 144 of the backing plate136. For example, the indentations 192 can be present as one or moregeometrically-shaped holes (e.g., circular, rectangular, or othergeometric shapes) or irregularly-shaped holes in the backing plate 136,one or more trenches or channels extending partially or fully along thebacking plate 136 (in the lateral, longitudinal, or diagonaldirections), and the like.

In these aspects, the material 116 can have two (or more) thicknessesdepending on whether a given portion of the material 116 extends intoone of the indentations. For ease of discussion and readability, thedry-state thickness 160 of the material 116, as used herein, refers to aportion of the material 116 (in a dry state) that does not extend intoone of the indentations, such as at locations 194. As such, thedry-state thickness 160 shown in FIG. 13 is the same as the dry-statethickness 160 shown above in FIG. 5.

Each indentation 192 may independently have a depth 196, which can rangefrom 1% to 200%, from 25% to 150%, or from 50% to 100% of the dry-statethickness 160 of the material 116. In these locations, the dry-statethickness of the material 116 is the sum of the dry-state thickness 160and the depth 196. FIG. 14 illustrates a variation on the indentations192 shown above in FIG. 13. In the design shown in FIG. 14, theindentations 192 can also extend in-plane with the backing plate 136 toform locking members 200 (e.g., arms or flanged heads). This design canalso be produced with co-extrusion or injection molding techniques, andcan further assist in mechanically securing the material 116 to thebacking plate 136.

As discussed above, the outsole 112 with the material 116 isparticularly suitable for use in global football/soccer applications.However, the material 116 can also be used in combination with othertypes of footwear 100, such as for articles of footwear 100 for golf(shown in FIG. 15), for baseball (shown in FIG. 16), and for Americanfootball (shown in FIG. 17), each of which can include traction elements114 as cleats, studs, and the like.

FIG. 15 illustrates an aspect in which the material 116 is positioned onone or more portions of the outsole 112 and/or cleats 114 in an articleof golf footwear 100. In some cases, the material 116 is present on oneor more locations of the ground-facing surface of the outsole 112 exceptthe cleats 114 (e.g., a non-cleated surface, such as generallyillustrated in FIG. 1 for the global football/soccer footwear 100).Alternatively or additionally, the material 116 can be present as one ormore film segments 116D on one or more surfaces between tread patterns202 on ground-facing surface of the outsole 112. Alternatively oradditionally, the material 116 can be incorporated onto one or moresurfaces of the cleats 114. For example, the material 116 can also be oncentral region of cleat 114 between the shafts/spikes 150A, such aswhere each cleat 114 is screwed into or otherwise mounted to the outsole112 backing plate 136, and has a generally flat central base region 158A(i.e., where the material 116 is located) and three shafts/spikes 150Aarranged around the perimeter of the central region 158A. In suchaspects, remaining regions of the outsole 112 can be free of thematerial 116. For example, the cleats 114 having material 116 can beseparate components that can be secured to the outsole 112 (e.g.,screwed or snapped in), where the outsole 112 itself can be free of thematerial 116. In other words, the material-covered cleats 114 can beprovided as components for use with standard footwear not otherwisecontaining the 116 (e.g., golf shoes or otherwise).

FIG. 16 illustrates an aspect in which the material 116 is positioned onone or more portions of the outsole 112 in an article of baseballfootwear 100. In some cases, the material 116 is present on one or morelocations of the ground-facing surface of the outsole 112 except thecleats 114 (e.g., a non-cleated surface, such as generally illustratedin FIG. 1 for the global football/soccer footwear 100). Alternatively oradditionally, the material 116 can be present as one or more filmsegments 116D on one or more recessed surfaces 204 in the ground-facingsurface of the outsole 112, which recessed surfaces 204 can include thecleats 114 therein (e.g., material 116 is located only in one or more ofthe recessed surfaces 204, but not substantially on the cleats).

FIG. 17 illustrates an aspect in which the material 116 is positioned onone or more portions of the outsole 112 in an article of Americanfootball footwear 100. In some cases, the material 116 is present on oneor more locations of the ground-facing surface of the outsole 112 exceptthe cleats 114 (e.g., a non-cleated surface, such as generallyillustrated in FIG. 1 for the global football/soccer footwear 100).Alternatively or additionally, the material 116 can be present as one ormore film segments 116D on one or more recessed surfaces 204 in theground-facing surface of the outsole 112, which recessed surfaces 204can include the cleats 114 therein (e.g., material 116 is located onlyin one or more of the recessed surfaces 204, but not substantially onthe cleats).

FIG. 18 illustrates an aspect in which the material 116 is positioned onone or more portions of the outsole 112 in an article of hiking footwear100 (e.g., hiking shoes or boots). As illustrated, the traction elements114 are in the form of lugs 114D which are integrally formed with andprotrude from the outsole 112 bottom surface 144. In some cases, thematerial 116 is present on one or more locations of the bottom surface144 of the outsole 112 except the lugs 114D. For example, the material116 can be located on recessed surfaces 204 between adjacent lugs 114D(e.g., but not substantially on the 114D).

The foregoing discussions of footwear 100 and outsole 112 have been madeabove in the context of footwear having traction elements (e.g.,traction elements 114), such as cleats, studs, spikes, lugs, and thelike. However, footwear 100 having material 116 can also be designed forany suitable activity, such as running, track and field, rugby, cycling,tennis, and the like. In these aspects, one or more segments of thematerial 116 are preferably located in interstitial regions between thetraction elements, such as in the interstitial grooves of a running shoetread pattern.

The outsoles and/or articles of footwear of the present disclosure,including the material present on (secured to) the outsoles and/orarticles of footwear described herein, can be characterized based onvarious properties, for example, soil shedding ability, water uptake,durability, melt flow rate, density, and/or various dynamic mechanicalproperties.

The material can be characterized by its ability to shed soil asdetermined by the impact energy required to dislodge soil from a sampleof material, and as measured according to the Impact Energy Testdisclosed herein. The material can be tested either in neat materialform or on a test sample taken from an outsole in accordance with theSampling Procedures disclosed herein. As shown in Table I (below), whentested according to the Impact Energy Test, the impact energy requiredto dislodge soil from a sample of a material according to the presentdisclosure was 0 Joules (i.e., the soil did not adhere to the sample).In comparison, the impact energy required to dislodge soil from a sampleof a material not in accordance with the present disclosure (and havinga thickness of 0.7 mm) was 0.55 Joules. Further, the impact energyrequired to dislodge soil from another sample of a material not inaccordance with the present disclosure (and having a thickness of 0.9mm) was 0.36 Joules. Accordingly, in some aspects, the impact energyrequired to dislodge soil from the material disclosed herein can rangefrom 0 Joules to 0.6 Joules, from 0 Joules to 0.4 Joules, from 0 Joulesto 0.2 Joules, or from 0.2 Joules to 0.4 Joules.

The ability of the material to take up water can reflect its abilityprevent soil accumulation during use with an article of footwear (e.g.,footwear 100). As discussed above, in some aspects when the material ispresent as an open-cell foam, it can take up u water. When the materialis then subjected to an application of pressure, either compressive orflexing, the material can reduce in volume to expel at least a portionof its water.

This expelled water is believed to reduce the adhesive/cohesive forcesof soil particles at the outsole, which taken alone, or more preferablyin combination with the material compliance, can prevent or otherwisereduce soil accumulation at the outsole. Accordingly, the material canundergo dynamic transitions during and between foot strikes, such aswhile a wearer is running or walking.

The material also can be characterized based by the durability of itssoil-shedding ability. The durability of the material can be assessedusing the Impact Energy Test, before use and after a certain specifiedperiod of time of use during normal activity conditions (e.g., in-gameuse). For example, the impact energy required to shed soil from thematerial can remain the same as when tested before use or vary by lessthan 10% of the impact energy required to dislodge soil before use andfollowing 90 minutes, 10 hours, 20 hours, 40 hours, 80 hours, 100 hours,or 200 hours (e.g., at least 80-100 hours) of game play, ascharacterized by the Impact Energy Test using the Footwear SamplingProcedure.

The material, as well as components of the material, can becharacterized based on melt flow rate. The melt flow rate melt flow rateof the material can be determined according to ASTM D1238 using a 2160 gweight and a temperature of 190° C. The melt flow rate of the material,according to ASTM D1238 using a 2160 g weight and a temperature of 190°C., can be from 0.4 g/10 mins. to 125 g/10 mins., or from 0.5 g/10 mins.to 100 g/10 mins.

The material can be characterized based on its density. The density ofthe material can be determined using standard gravimetric and volumetricprocedures. The density of the material can be from 0.5 lbs./ft.³ to 5lbs./ft.³, or from 1 lb./ft.³ to 3.5 lbs./ft.³.

The material can be characterized based on its tensile strength. Thetensile strength of the material can be determined on standard tensilespecimens of the material using a standard method such as ASTM D882. Thetensile strength of the material, according to ASTM D882, can be from 75kPa to 250 kPa, or from 100 kPa to 200 kPa.

The material can be characterized based on its Young's modulus (i.e.,tensile modulus). The Young's modulus of the material can be calculatedby dividing the tensile stress by the extensional strain of thematerial, which can be obtained from a stress-strain curve for thematerial as determined using standard procedures. The Young's modulus ofthe material can be from 0.4 MPa to 2.5 MPa, or from 0.5 MPa to 2 MPa.

The material 116 is composed of a polymer material that optionally canbe formulated with an agent for cross-linking and optionally can befoamed. The material can comprise a blend of polymers and optionallynon-polymeric materials. The material is described in U.S. Pat. No.8,853,289, the disclosure of which is incorporated herein by reference.Therein the material is described in the context of cleaning up oilspills. There is no disclosure, teaching, or suggestion therein,however, that the material can be used in the manner now discovered asan article of footwear or a component of an article of footwear. Thematerial is believed to be commercially available from OPFLEXTechnologies LLC (Indianapolis, Ind.), the assignee of the '289 patent.

In some aspects, the material is low or medium density polyethylene incombination with (e.g., blended with) an ethylene alkyl acrylatecopolymer or a combination of alkyl acrylate copolymers. In one aspect,the ethylene alkyl acrylate copolymer is selected from the groupconsisting of ethylene-methyl acrylate, ethylene-ethyl acrylate, andmixtures thereof. These materials have a density ranging from about 0.85to about 0.95. Specifically, elastomers, such as polyolefin elastomersand ethylene-styrene copolymers have a density of about 0.85, and amelting point of about 45° C. Very low density polyethylene has adensity of about 0.89, and a melting point of about 93° C. Low densityand linear low density polyethylene has a density of about 0.91, and amelting point of about 100° C. Medium density polyethylene has a densityof about 0.92, and a melting point of about 112° C. In contrast highdensity polyethylene has a density of about 0.93, and a melting point ofabout 120° C.

In one aspect, when the material comprises polyethylene, thepolyethylene is selected from polyethylene resins with a density of fromabout 0.91 grams/cubic centimeter (g/cc) to about 0.950 g/cc, or of fromabout 0.917 g/cc to about 0.930 g/cc, or from about 0.917 g/cc to about0.923 g/cc. The material when in the form of a foam (e.g., open-cellfoam) can have a foamed density of about 1.5 pounds per cubic foot. Themelt flow rate, as determined according to ASTM D1238 using a 2160 gweight and a temperature of 190° C., can be in the range of from about0.5 g/10 mins. to about 100 g/10 mins., or from about 0.5 g/10 mins. toabout 10 g/10 mins., or from about 1 g/10 mins. to about 4 g/10 min.Polyethylene resins suitable for use are commercially available from avariety of manufacturers, such as Nova Chemical, Exxon Mobil, andWestlake Chemical. These resins are believed to be produced using a highpressure polyethylene process normally manufactured on either tubular orautoclave reactors.

The ethylene alkyl acrylate copolymers of the material can be copolymersof ethylene and methyl acrylate or ethyl acrylate or mixtures thereof.These copolymers can have alkyl acrylate content of from about 3% toabout 45%, based on the total weight of copolymer. The alkyl acrylatecontent can be from about 15% to about 25%. The melt flow rate asmeasured above is similar to the polyethylene melt flow rate. The meltflow rate range can be from about 0.5 g/10 mins. to about 4 g/10 mins.

The material can contain (a) about 20% to about 80% of the copolymer ora combination of two or more copolymers, and (b) about 80% to about 20%of the polyethylene. The range can be about 40% to about 60%copolymer(s), or about 50% to about 60% copolymer(s). The combinationalso may contain other polymers to enhance properties (e.g.,durability). Examples of other polymers include polyethylene,polyethylene acrylate, and ethylene-propylene diene monomer (EPDM). EPDMis a synthetic rubber analog that can enhance the elongationalproperties (e.g., elongation to yield or break) and, therefore, canenhance durability properties.

An agent suitable to cross-link the polymer (a crosslinking agent) mayalso be included. Suitable chemical crosslinking agents include organicperoxides, silanes, vinyl monomers, organo-titanates, organo-zirconates,and p-quinone dioximes. One method of cross-linking employs an organicperoxide, examples of which include dicumyl peroxide,2,5-dimethyl-2,5-di(t-butylperoxy)hexane,1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane,1,1-di-(t-butylperoxy)cyclohexane,2,2′-bis(t-butylperoxy)-diisopropylbenzene,4,4′-bis(t-butylperoxy)butylvalerate, t-butylperbenzoate,t-butylpaterephthalate, and t-butyl peroxide. Preferably, the peroxidecross-linking agent is dicumyl peroxide or2,2′-bis(t-butylperoxy)diisopropylbenzene.

The cross-linked polymer optionally can be grafted. Generally, graftinginvolves attaching monomer(s) or polymer(s) to the original polymerresin chains. Grafting is accomplished by forming active grafting siteson the original polymer chains in the presence of monomers that canfurther polymerize as branches from the original polymer chains. Activegrafting sites can be formed, for example, by free radicals or anions. Agraft can include other monomers, such as di- and tri-allyl cyanuratesand isocyanurates, alkyl di- and tri-acrylates and methacrylates, zincdimethacrylates and diacrylates, styrenes, divinylbenzene, vinyl silaneswith at least two hydrolysable groups, and butadiene. Silane-graftedpolymer materials can be cross-linked by reaction with moisture. Thepolymer may also be grafted with maleic anhydride to modify theabsorption properties.

A polyolefin elastomer optionally may be included in the material.Polyolefin elastomers are modifiers that provide improvements in impactstrength and other properties. In one aspect, the polyolefin elastomeris a metallocene polymer, such as Engage™ (available from The DowChemical Company (Midland, Mich.)), or equivalent. In an aspect, aportion or all of the ethylene-alkyl acrylate may be replaced with ametallocene polymer.

Unimpregnated polyethylene-polystyrene (UPES) also may be included inthe material. UPES is compatible with various polymers and improvesprocessability. UPES may provide additional flexibility, improved meltstrength, increased temperature range, density potential, and sourcereduction.

Chemical foaming agents also may be included in the material in order toform the material into an open-cell foam. Chemical foaming agents mayinclude, for example, azodicarbonamide, p-p′-oxybis(benezene)sulfonylhydrazide, p-toluenesulfonyl semicarbazide, 5-plienyltetrazole,ethyl-5-phenyltetrazole, dinitrosopentamethylenetetramine, and otherazo, N-nitroso, semicarbazide, sulfonyl hydrazides, carbonate, andbicarbonate compounds that decompose to form a gas when heated. Chemicalfoaming agents, such as azodicarbonamide, can be used. Maleic anhydridecan be added to the material to increase the polarity of the materialcomposition to further improve water absorption.

The material also may include additives. Additives may include inertfillers such as calcium carbonate, talc, zinc oxide, or the like. Thesefillers can serve to lower the ultimate elongation of the foam walls,yielding easier crushing tendency. Silicone oil also can be added tomodify the integrity of the cell wall and to create an even cellularstructure. In an aspect, zinc stearate may be included to act as afoaming agent activator. In an aspect, stearic acid may be used as areleasing agent. Other additives, alone or in combination, can be addedto the foam compositions including antioxidants, ultra-violetstabilizers, thermal stabilizers, antistatic components, flameretardants, dyes, pigments or colorants, and other processing aids.

When present in the form of an open-cell foam, the material has aninterconnecting cell structure. In one example, the foam is prepared bymixing the polyethylene and copolymer with a foaming agent, cross-linkerand any desired additive. The cross-linker effects cross-linking of thematerial of polyethylene and copolymer. The mixture is then directed toa mold under high pressure where the mixture is subjected to heat andpressure where the cross-linking is initiated. The mixture then isdirected to a second step expansion chamber where it is steam heated andwater cooled. In this process, there is no direct contact with theheating and cooling fluids. In this step the foaming agent decomposesinto a gas while cross-linking is continued. The foam mixture is thencooled and removed for further processing. The foam is then crushed topuncture its skin and then compressed to break the closed cells. Thefoam then optionally can be crushed or punctured with needles toincrease the number and size of the open cells.

Alternatively, the foam can be continuously produced through extrusionfoaming. In such a process, all of the ingredient components are addedto an extruder as neat resin/filler or as masterbatches from a previouscompounding step. The components form a molten resin that flows throughan extruder and later exits through an extrusion die. As the moltenresin exits the die a large pressure drop results and acts to separate agas phase from the solid material. Thereafter, post-processing can beused to alter the skin properties or emboss the material on amacroscale.

The articles of footwear of the present disclosure can be manufacturedusing a variety of different footwear manufacturing techniques. Forexample, the material (e.g., material 116) and the optional backingplate or substrate can be formed using methods such as injectionmolding, cast molding, thermoforming, vacuum forming, extrusion, spraycoating, and the like.

In a first aspect, the outsole is formed with the use of a co-extrudedoutsole plate. In this case, the film material can be co-extruded with athermoplastic material used to form a thin backing substrate, where theresulting co-extrudate can be provided in a web or sheet form. The webor sheet can then be placed in a vacuum thermoforming tool to producethe three-dimensional geometry of the outsole ground-facing side(referred to as an outsole face precursor). The backing substrateprovides a first function in this step by creating a structural supportfor the relatively thinner and weaker material (e.g. material 116). Theoutsole face precursor can then be trimmed to form its perimeter andorifices to receive traction elements, thereby providing an outsoleface.

The outsole face can then be placed in a mold cavity, where the materialis preferably positioned away from the injection sprues. Anotherthermoplastic material can then be back injected into the mold to bondto the backing substrate, opposite of the material (e.g., material 116).This illustrates the second function of the backing substrate, namely toprotect the material (e.g., material 116) from the injection pressure.The injected thermoplastic material can be the same or different fromthe material used to produce the backing substrate. Preferably, theyinclude the same or similar materials (e.g., both being thermoplasticpolyurethanes). As such, the backing substrate and the injected materialin the mold form the outsole backing plate, which is secured to thematerial disclosed herein (e.g., material 116) (during the co-extrusionstep).

In a second embodiment, the outsole is formed with the use of injectionmolding. In this case, a substrate material is preferably injected intoa mold to produce the outsole backing plate. The outsole backing platecan then be back injected with the material disclosed herein (e.g.,material 116) to produce the material bonded to the outsole backingplate.

In either embodiment, after the outsole is manufactured, it can bedirectly or indirectly secured to a footwear upper to provide thearticle of footwear of the present disclosure. In particular, materialdisclosed herein (e.g., material 116) can function as a ground-facingsurface of the outsole, which is positioned on the opposite side of theoutsole backing plate from the upper.

Property Analysis and Characterization Procedures

Various properties can be determined for the material secured to theoutsole according to the following methodologies.

The terms “Footwear Sampling Procedure,” “Neat Material SamplingProcedure,” “Water Uptake Capacity Test,” and “Impact Energy Test,” asused herein refer to the respective sampling procedures and testmethodologies described below. These sampling procedures and testmethodologies characterize the properties of the recited materials,outsoles, footwear, and the like, and are not required to be performedas active steps in the claims.

1. Sampling Procedures

As mentioned above, it has been found that when the material is securedto another substrate, the interfacial bond can restrict the extent thatthe material can take up water. As such, various properties of thematerial can be characterized using samples prepared with the followingsampling procedures:

A. Footwear Sampling Procedure

This procedure can be used to obtain a sample of the material when thematerial is a component of a footwear outsole or article of footwear(e.g., bonded to an outsole substrate, such as an outsole backingplate). An outsole sample including the material in a non-wetted state(e.g., at 25° C. and 20% relative humidity) is cut from the article offootwear using a blade. This process is performed by separating theoutsole from an associated footwear upper, and removing any materialsfrom the outsole top surface (e.g., corresponding to the top surface142) that can uptake water and potentially skew the water uptakemeasurements of the outsole film. For example, the outsole top surfacecan be skinned, abraded, scraped, or otherwise cleaned to remove anyupper adhesives, yarns, fibers, foams, and the like that couldpotentially take up water themselves.

The resulting sample includes the material and any outsole substratebonded to the material, and maintains the interfacial bond between thematerial and the associated substrate. As such, this test can simulatehow the material will perform as part of an article of footwear.Additionally, this sample is also useful in cases where the interfacialbond between the material and the outsole substrate is less defined,such as where the material is highly diffused into the outsole substratematerial (e.g., with a concentration gradient).

The sample is taken at a location along the outsole that provides asubstantially constant material thickness (within +/−10% of the averagematerial thickness), such as in a forefoot region, midfoot region, or aheel region of the outsole, and has a surface area of 4 squarecentimeters (cm²). In cases where the material is not present on theoutsole in any segment having a 4 cm² surface area, sample sizes withsmaller cross-sectional surface areas can be taken and the area-specificmeasurements are adjusted accordingly.

B. Neat Material Sampling Procedure

This procedure can be used to obtain a sample of a material when thematerial is isolated in a neat form (i.e., without any bondedsubstrate). In this case, the material is extruded as a web or sheethaving a substantially constant thickness (within +/−10% of the averagematerial thickness), and cooled to solidify the resulting web or sheet.A sample of the material having a surface area of 4 cm² is then cut fromthe resulting web or sheet.

Alternatively, if a source of the material is not available in a neatform, the material can be cut from an outsole substrate of a footwearoutsole, or from a backing substrate of a co-extruded sheet or web,thereby isolating the material. In either case, a sample of the materialhaving a surface area of 4 cm² is then cut from the resulting isolatedmaterial.

2. Water Uptake Capacity Test

This test measures the water uptake capacity of the material after agiven soaking duration for a sample taken with the above-discussedFootwear Sampling Procedure, or the Neat Material Sampling Procedure.The sample is initially dried at 60° C. until there is no weight changefor consecutive measurement intervals of at least 30 minutes apart(e.g., a 24-hour drying period at 60° C. is typically a suitableduration). The total weight of the dried sample (Wt,_(sample,dry)) isthen measured in grams. The dried sample is then allowed to cool down to25° C., and is fully immersed in a deionized water bath maintained at25° C. After a given soaking duration, the sample is removed from thedeionized water bath, blotted with a cloth to remove surface water, andthe total weight of the soaked sample (Wt,_(sample,wet)) is measured ingrams.

Any suitable soaking duration can be used, where a 24-hour soakingduration is believed to simulate saturation conditions for the materialof the present disclosure. Accordingly, as used herein, the expression“having a water uptake capacity at 5 minutes of . . . ” refers to asoaking duration of 5 minutes, having a water uptake capacity at 1 hourof . . . ” refers to a soaking duration of 1 hour, the expression“having a water uptake capacity at 24 hours of . . . ” refers to asoaking duration of 24 hours, and the like.

As can be appreciated, the total weight of a sample taken pursuant tothe Footwear Sampling Procedure includes the weight of the material ofthe present disclosure as dried or soaked (Wt,_(mat.,dry) orWt,_(mat.,wet)) and the weight of the outsole or backing substrate(Wt,_(substrate)). In order to determine a change in weight of thematerial of the present disclosure due to water uptake, the weight ofthe substrate (Wt,_(substrate)) needs to be subtracted from the samplemeasurements.

The weight of the substrate (Wt,_(substrate)) is calculated using thesample surface area (e.g., 4 cm²), an average measured thickness of thesubstrate in the sample, and the average density of the substratematerial. Alternatively, if the density of the material for thesubstrate is not known or obtainable, the weight of the substrate(Wt,_(substrate)) is determined by taking a second sample using the samesampling procedure as used for the primary sample, and having the samedimensions (surface area and film/substrate thicknesses) as the primarysample. The outsole film of the second sample is then cut apart from thesubstrate of the second sample with a blade to provide an isolatedsubstrate. The isolated substrate is then dried at 60° C. for 24 hours,which can be performed at the same time as the primary sample drying.The weight of the isolated substrate (Wt,_(substrate)) is then measuredin grams.

The resulting substrate weight (Wt,_(substrate)) is then subtracted fromthe weights of the dried and soaked primary sample (Wt,_(sample,dry) andWt,_(sample,wet)) to provide the weights of the material of the presentdisclosure as dried and soaked (W,t_(mat.,dry) and Wt,_(mat.,wet)), asdepicted below by Equations 1 and 2:Wt, _(mat.,dry) =Wt, _(sample,dry) −Wt, _(substrate)   (Equation 1)Wt _(mat.,wet) =Wt _(sample,wet) =Wt _(substrate)   (Equation 2)

For material samples taken pursuant to the Neat Material SamplingProcedure, the outsole/backing substrate weight (Wt,_(substrate)) iszero. As such, Equation 1 collapses to Wt Wt,_(sample,dry), and Equation2 collapses to Wt,_(mat.,wet)=Wt,_(sample,wet).

The weight of the dried material (Wt,_(mat,dry)) is then subtracted fromthe weight of the soaked material (Wt,_(mat.,wet)) to provide the weightof water that was taken up by the material, which is then divided by theweight of the dried material (Wt,_(mat.,dry)) to provide the wateruptake capacity for the given soaking duration as a percentage, asdepicted below by Equation 3:

$\begin{matrix}{{{Water}\mspace{14mu}{Uptake}\mspace{14mu}{Capacity}} = {\frac{{Wt},_{{{mat}.},{wet}}{- {Wt}},_{{{mat}.},{dry}}}{{Wt},_{{{mat}.},{dry}}}\left( {100\%} \right)}} & \left( {{Equation}\mspace{14mu} 3} \right)\end{matrix}$

For example, a water uptake capacity of 50% at 1 hour means that thesoaked material weighed 1.5 times more than its dry-state weight aftersoaking for 1 hour, where there is a 1:2 weight ratio of water tomaterial. Similarly, a water uptake capacity of 500% at 24 hours meansthat the soaked material weighed 5 times more than its dry-state weightafter soaking for 24 hours, where there is a 4:1 weight ratio of waterto material.

3. Impact Energy Test

This test measures the ability of a sample of the material of thepresent disclosure to shed soil under particular test conditions, wherethe sample is prepared using the Neat Film Sampling Procedure (to obtaina suitable sample surface area). Initially, the sample is fully immersedin a water bath maintained at 25° C. for 24 hours), and then removedfrom the bath and blotted with a cloth to remove surface water.

The saturated test sample is then adhered to an aluminum block modeloutsole having a 25.4-millimeter thickness and a 76.2 millimeters×76.2millimeters surface area, using a room temperature-curing two-part epoxyadhesive commercially available under the tradename “LOCTITE 608” fromHenkel, Düsseldorf, Germany. The adhesive is used to maintain theplanarity of the soaked sample, which can curl when saturated.

Four polyurethane cleats, which are commercially available under thetrade name “MARKWORT M12-EP” 0.5-inch (12.7 millimeter) tall cleats fromMarkwort Sporting Goods Company, St. Louis, Mo., are then screwed intothe bottom of the block in a square pattern with a 1.56-inch(39.6-millimeter) pitch. As a control reference, four identical cleatsare attached to an aluminum block model outsole without having attacheda sample of the material of the present disclosure.

To clog the model outsole cleats, a bed of soil of about 75 millimetersin height is placed on top of a flat plastic plate. The soil iscommercially available under the tradename “TIMBERLINE TOP SOIL,” model50051562, from Timberline (subsidiary of Old Castle, Inc., Atlanta, Ga.)and was sifted with a square mesh with a pore dimension of 1.5millimeter on each side. The model outsole is then compressed into thesoil under body weight and twisting motion until the cleats touch theplastic plate. The weight is removed from the model outsole, and themodel outsole is then twisted by 90 degrees in the plane of the plateand then lifted vertically. If no soil clogs the model outsole, nofurther testing is conducted.

However, if soil does clog the model outsole, the soil is knocked looseby dropping a 25.4-millimeter diameter steel ball weighing 67 grams ontothe top side of the model outsole (opposite of the test sample andclogged soil). The initial drop height is 152 millimeters (6 inches)above the model outsole. If the soil does not come loose, the ball dropheight is increased by an additional 152 millimeters (6 inches) anddropped again. This procedure of increasing the ball drop height by 152millimeter (6 inch) increments is repeated until the soil on the bottomof the outsole model is knocked loose.

This test is run 10 times per test sample. For each run, the ball dropheight can be converted into unclogging impact energy by multiplying theball drop height by the ball mass (67 grams) and the acceleration ofgravity (9.8 meters/second). The unclogging impact energy in Joulesequals the ball drop height in inches multiplied by 0.0167. Theprocedure is performed on both the model outsole with the sample ofmaterial of the present disclosure and a control model outsole withoutthis sample, and the relative ball drop height, and therefore relativeimpact energy, is determined as the ball drop height for the modeloutsole with the sample divided by the control model outsole without thesample. A result of zero for the relative ball drop height (or relativeimpact energy) indicates that no soil clogged to the model outsoleinitially when the model outsole was compressed into the test soil(i.e., in which case the ball drop and control model outsole portions ofthe test are omitted).

4. Average Cell Diameter Determination

As previously noted herein, the material, when present in the form of anopen-cell foam, preferably has a specified average cell diameter. Thatdiameter can be determined in accordance with an art-recognizedprocedure. Specifically, cell morphology can be assessed with a scanningelectron microscope (SEM) that offers the ability to determine theaverage cell diameter of an open-cell foam. Three samples may be cut todimensions of 100×100×7.5 mm at various locations along a sample of thefoam. Image capture of cross-sectional cell structure on the foamsurface can be facilitated by evenly applying a thin layer of blackpaint on the top of each test sample. An arbitrary square frame testarea (of, for example, 247 square millimeters) may be chosen and datamay be obtained from the measurement of about 500 cells within this testarea.

Image analysis can be conducted using a Quantimet Image Analyzer offeredby Leica Microsystems (Cambridge, UK). The image that may appear on acomputer screen may need to be manipulated by adjusting the gray scaleuntil most of the cell walls appear to be intact. When the image at anappropriate threshold has been defined, it may then be reconstructedinto a form in which the computer can distinguish the features ofinterest and make the measurements for any specified requirement. Thisreconstruction can be accomplished by various image processing commandsbuilt into the analyzer's software. This software can also estimatevarious parameters, including, for example, cell area, equivalent celldiameter, and the aspect ratio. These parameters, as well as an averagecell diameter, can be calculated according to the equations describedbelow.

The mean area (A) of a set of open-cells with individual area (A_(i))(where i=1 to n) is defined by Equation (5):

$\begin{matrix}{A = \left( {\sum\limits_{i = 1}^{n}\frac{A_{i}}{n}} \right)} & \left( {{Equation}\mspace{14mu} 5} \right)\end{matrix}$

Even though the cells within the foam may not be spherical, it is commonpractice to consider the equivalent cell diameter (D_(equiv)) as acharacteristic dimension, calculated according to Equation (6):

$\begin{matrix}{d_{{equiv},i} = \sqrt{\frac{4\; A_{i}}{\pi}}} & \left( {{Equation}\mspace{14mu} 6} \right)\end{matrix}$

An average cell diameter (D) can be determined by Equation (7):

$\begin{matrix}{D = \left( {\sum\limits_{i = 1}^{n}\frac{D_{{equiv},i}}{n}} \right)} & \left( {{Equation}\mspace{14mu} 7} \right)\end{matrix}$

The aspect ratio, if desired, can be determined by the ratio of themaximum length to the minimum width of a truncated cell. Thus, when theratio is 1, the cell shape can be considered to be circular, or almostcircular.

5. Oil Absorption Test

The Oil Absorption Test may be used to determine the capacity of the ofthe material to absorb oil, especially, when the material is present inthe form of an open-cell foam. This test uses SAE 10W-30 weight oil. Thetesting is generally described in U.S. Pat. No. 8,853,239, thedisclosure of which is incorporated herein by reference. As describedthere, three samples of foam approximately 3×3×0.25 inches are used foreach test. The samples may be obtained according to the FootwearSampling Procedure or the Neat Material Sampling Procedure, describedabove.

The samples are floated on the oil surface for approximately six hours.The samples should not be squeezed or manipulated during the test. Thesamples are weighed before and after the test. The samples are pressedto a thickness of approximately 0.015 inch to remove oil, or some otherthickness so long as each sample is similarly pressed. The sample isthen placed between two polyethylene plates and squeezed using amechanical vise. The samples are then doubled over and re-squeezed andweighed. The samples are then immediately returned to the oil. Thesamples are removed from the oil after approximately 6 hours and againweighed. The squeezing procedure can be repeated and the samples can bere-weighed. The samples are then returned to oil for a third time, for24 hours, to determine maximum oil absorption. The oil is allowed todrip from the sample for approximately one minute prior to weighing sothat only retained oil is included in the weight measurement.

The oil absorption weight capacity of the sample is the ratio of (i) theweight of the sample plus the oil to (ii) the original weight of thesample. As noted above, the material, when present in the form of anopen-cell foam, can absorb as much as 27 times its own weight in oil,according to the Oil Absorption Test. Thus, the open-cell foam materialobtained in accordance with the Footwear Sampling Procedure or the NeatMaterial Sampling Procedure can have an oil absorption weight capacityof SAE 10W-30 oil of least 27 times its weight, as determined accordingto the Oil Absorption Test.

EXAMPLES

The present disclosure is more particularly described in the followingexamples that are intended as illustrations only, since numerousmodifications and variations within the scope of the present disclosurewill be apparent to those skilled in the art. Unless otherwise noted,all parts, percentages, and ratios reported in the following examplesare on a weight basis, and all reagents used in the examples wereobtained, or are available, from the chemical suppliers described below,or may be synthesized by conventional techniques.

Water Uptake

A sample of Oplex Foam (obtained from OPFLEX Technologies LLC(Indianapolis, Ind.)) was analyzed for the water uptake rate proceduredescribed above after soaking the dried sample in deionized water for 60minutes. The sample was circular, about 25 mm in diameter. The sampleexhibited a 15% weight gain of material at 60 minutes.

Impact Energy

Three samples of open-cell foams were analyzed for soil sheddingaccording to the Impact Energy Test described above using an aluminummodel outsole to which each of the samples was affixed. The results forimpact energy calculated from ball drop height are shown in Table Ibelow. A sample of Oplex Foam was obtained from OPFLEX Technologies LLC(Indianapolis, Ind.).

TABLE I Impact Energy Test Data Sample Impact Energy (Joules) OpFlex 0Polypropylene foam 0.7 mm 0.55 Polypropylene foam 0.9 mm 0.36Field Test

Standard soccer boots with thermoplastic polyurethane outsoles weremodified by affixing material according to the disclosure to theground-facing surfaces of their outsoles, including the cleats. In onefield test, three pairs of boots included an Opflex Foam layer having athickness of 3 mm, another three pairs of boots included an Opflex Foamlayer having a thickness of 1 mm, and yet another pair of boots—controlboots—did not include any such layer (i.e., the control soccer bootswere identical to the test boots except the control boots did notinclude the material on the ground-facing surface of their outsoles).The boots, all initially clear of all debris, were then worn by playersin a controlled outdoor setting while playing soccer for 90 minutesduring a rainy day. 45 minutes were played on a natural grass field, and45 minutes were played on an organic/sand/clay mix field. After the90-minute playing session, the boots were investigated for theaccumulation of soil (including debris) over the course of the game.FIG. 19 depicts the boots after this playing session. FIGS. 19A and 19Bshow the pairs of boots with the Opflex Foam layer. Specifically, FIG.19A shows the ground-facing surface of the outsole having the 3 mm thickOpflex Foam layer. FIG. 19B shows the ground-facing surface of theoutsole having the 1 mm thick Opflex Foam layer. FIGS. 19C, 19D, 19E,and 19F each show the ground-facing outsoles of the control pair ofboots. As seen from the images in FIG. 19, the pairs of boots with theOplex Foam accumulated little to no soil, while the pair of controlboots accumulated a substantial amount of soil.

In another field test, the weight of boots with outsoles including thematerial according to the disclosure was compared to the weight of boots(control boots) that lacked the material according to the disclosure.The control pair of boots were soccer boots which were identical to thetest boots except that they lacked any material (according to thedisclosure). The test boots were identical to the control boots, exceptthat greater than 80% of the ground-facing outsole thereof had affixedto it an Opflex Foam layer having a thickness of 1 mm. The boots, bothinitially clear of all soil, were initially weighed and then were wornby players in a controlled outdoor setting while playing soccer for 45minutes during a rainy day on a natural grass field. After the 45-minuteplaying session, the boots were again weighed. The control bootsincreased in weight by 31%. In contrast, the test boots increased inweight by only 11%. In each case, the weight gain was attributed toaccumulated soil, including grass clippings. Thus, the article offootwear having the material (in this case, open-cell foam material)secured to a ground-facing surface prevents or reduces soil accumulationon the outsole of the footwear, such that the article of footwearretains at least 10% or at least 20% less soil by weight as compared toa second article of footwear which is identical except that the secondarticle of footwear is free of the open-cell foam material, when the twoarticles of footwear are worn under identical conditions.

Although the present disclosure has been described with reference topreferred embodiments, workers skilled in the art will recognize thatchanges may be made in form and detail without departing from the spiritand scope of the disclosure.

What is claimed is:
 1. An article of footwear, the article comprising:an outsole having a ground-facing surface, an open-cell foam materialsecured to at least a portion of the ground-facing surface and aplurality of traction elements secured to the ground-facing surface,wherein the open-cell foam material has an average cell diameter rangingfrom 0.65 mm to 1.4 mm, wherein the open-cell foam material comprises anethylene-alkyl acrylate copolymer component; and an upper secured to theoutsole; wherein the article of footwear prevents or reduces soilaccumulation on the outsole such that the article of footwear retains atleast 10% less soil by weight as compared to a second article offootwear which is identical to the article of footwear except that thesecond article of footwear is free of the open-cell foam material. 2.The article of claim 1, wherein the plurality of traction elementscomprise a plurality of cleats.
 3. The article of claim 2, wherein thematerial is not present on or in direct contact with the plurality ofcleats.
 4. The article of claim 1, wherein the outsole as characterizedby a Neat Material Sampling Procedure has an impact energy of from 0Joules to 0.6 Joules according to an Impact Energy Test.
 5. The articleof claim 1, wherein the open-cell foam material as characterized by aNeat Material Sampling Procedure has an absorption weight capacity ofSAE 10W-30 oil of at least 27 times its weight of the open-cell foammaterial according to the Oil Absorption Test.
 6. The article of claim1, wherein the open-cell foam material has a melt flow rate in a rangeof between about 0.5 g/10 mins. and about 100 grams/10 mins according toASTM D1238 using a 2160 g weight and a temperature of 190° C.
 7. Thearticle of claim 1, wherein the ethylene-alkyl acrylate copolymercomponent consists of an ethylene-alkyl acrylate copolymer or acombination of two or more ethylene-alkyl acrylate copolymers.
 8. Thearticle of claim 7, wherein a concentration of the ethylene-acrylatecopolymer component present in the open-cell foam is from 40 to 80 partsper hundred by weight based on a total polymer content of the open-cellfoam.
 9. The article of claim 7, the ethylene-alkyl acrylate copolymercomponent comprises a copolymer of ethylene and methyl acrylate, or acopolymer of ethylene and ethyl acrylate, or a combination of both. 10.The article of claim 7, wherein the ethylene-alkyl acrylate copolymercomponent comprises an ethylene-alkyl acrylate copolymer having an alkylacrylate content of between 3% and 45%, based on a total weight of thecopolymer.
 11. The article of claim 1, wherein the open-cell foammaterial has a thickness in a dry state of about 0.1 mm to about 12 mm.12. The article of claim 1, wherein the open-cell foam material has atensile strength of 75 kiloPascals (kPa) to 250 kPa, as determinedaccording to ASTM D882.
 13. The article of claim 1, wherein theopen-cell foam material has a Young's modulus of from 0.4 megaPascals(MPa) to 2.5 MPa.
 14. The article of claim 1, wherein each of theplurality of traction elements comprises a terminal edge, and whereinthe open-cell foam material is not present on the terminal edges of anyof the plurality of traction elements.
 15. The article of claim 1,wherein one or more of the traction elements is selected from the groupconsisting of: a cleat, a stud, a spike, and a lug.
 16. The article ofclaim 1, wherein the traction elements are integrally formed with theoutsole.
 17. The article of claim 1, wherein the traction elements areremovable traction elements.
 18. A method of use of an article offootwear, the method comprising: providing an article of footwearcomprising an outsole having a ground-facing surface, an open-cell foammaterial secured to at least a portion of the ground-facing surface anda plurality of traction elements secured to the ground-facing surface,wherein the open-cell foam material has an average cell diameter rangingfrom 0.65 mm to 1.4 mm, wherein the open-cell foam material comprises anethylene-alkyl acrylate copolymer component; and wearing the article offootwear under conditions in which the outsole comes into direct contactwith wet soil, wherein the article of footwear prevents or reducesaccumulation of the soil on the outsole such that the article offootwear retains at least 20% less soil by weight as compared to asecond article of footwear worn under identical conditions wherein thesecond article of footwear is identical to the article of footwearexcept that the second article of footwear is free of the open-cell foammaterial.
 19. The method of claim 18, wherein the plurality of tractionelements comprise a plurality of cleats.
 20. The method of claim 19,wherein the open-cell foam is not present on or in direct contact withthe plurality of cleats.
 21. The method of claim 18, wherein the outsoleas characterized by a Neat Material Sampling Procedure exhibits animpact energy of from 0 Joules to 0.6 Joules according to an ImpactEnergy Test.
 22. The method of claim 18, wherein the outsole ascharacterized by a Neat Material Sampling Procedure exhibits an impactenergy of from 0.2 Joules to 0.4 Joules.
 23. The method of claim 18,wherein the ethylene-alkyl acrylate copolymer component consists of anethylene-alkyl acrylate copolymer or a combination of two or moreethylene-alkyl acrylate copolymers.
 24. The method of claim 23, whereina concentration of the ethylene-acrylate copolymer component present inthe open-cell foam material is from 40 to 80 parts per hundred by weightbased on a total polymer content of the open-cell foam material.
 25. Themethod of claim 1, wherein each of the plurality of traction elementscomprises a terminal edge, and wherein the open-cell foam material isnot present on the terminal edges of any of the plurality of tractionelements.
 26. The method of claim 1, wherein one or more of the tractionelements is selected from the group consisting of: a cleat, a stud, aspike, and a lug.
 27. The method of claim 1, wherein the tractionelements are integrally formed with the outsole.
 28. The method of claim1, wherein the traction elements are removable traction elements.